Among the current therapies for the treatment of AK are excisional surgery, cryosurgery, electrodessication and curettage, topical chemotherapy and light therapies. With provider-administered devices, temperature utilized, times of contact, and other variations in administration, influence efficacy of treatment. Efficacy can be improved by increasing the freeze time, but this is often associated with greater discomfort, more severe skin necrosis, and increased risk of post-treatment hypopigmentation. In addition, as with other lesion-directed therapies, cryosurgery does not treat subclinical lesions in the surrounding skin. Treated lesion clearance rates at 3 months post-treatment after double-freeze thaw cryotherapy has been reported to be around 76-88%; however, new lesions in the treatment field were not included. Overall lesion clearance rate, including new subclinical lesions, at approximately 5 months post-cryosurgery has been reported to be 35-51%. There is limited information on long-term AK clearance rates after cryosurgery and those reports differ in their methods of calculation. In a study comparing cyrotherapy, imiquimod and 5-fluorouracil, at 12 months post cryotherapy 28% (7/25) had complete clearance of baseline lesions that had undergone cryotherapy, but only 4% (1/25) had complete clearance of the treatment field.